The present invention relates to optics and controlling the transmission of light energy and more particularly to a polarization maintaining optical device or switch.
Optical systems that use polarization dependent devices, such as liquid crystals, waveguides, optical instrumentation, and optical test equipment or other polarization dependent elements or devices require that the proper polarization of light energy or a light beam be maintained through the system. Optical switches are sometimes used in such systems to cross-connect optical devices or to control emission of the light energy for signaling purposes or other purposes. For example, electro-optic modulators that are polarization dependent are commonly used in fiber optical networks. Some applications require routing the output from a first set of modulators to the input of a second set of modulators using a fiber optical cross-connect switch for signal interleaving and optical encryption or for other purposes. Using a polarization maintaining fiber optical cross-connect switch will minimize polarization dependent loss and maintain signal integrity.
Another example of a need to maintain polarization is automated testing of multi-channel polarization dependent fiber optical devices. A polarization maintaining fiber optical switch is needed to switch polarized light into different channels of the polarization device under test. Optical switches are currently being used in telecom applications but these known switches do not maintain the polarization orientation of the input light beams.